(a) The commissioners court of a county, any part of which is located within 57 miles of a major astronomical observatory at the McDonald Observatory, shall adopt orders regulating the installation and use of outdoor lighting in any unincorporated territory of the county.
(b) On the request of the director of the George Observatory or the Stephen F. Austin State University Observatory, the commissioners court of a county, any part of which is located within five miles of a major astronomical observatory at the George Observatory or the Stephen F. Austin State University Observatory, may adopt orders regulating the installation and use of outdoor lighting in any unincorporated territory of the county.

(b-1) This subsection applies only to a county with a population of more than one million that has at least five United States military bases and to any county adjacent to that county that is within five miles of a United States Army installation, base, or camp. On the request of a United States military installation, base, or camp commanding officer, the commissioners court of a county subject to this subsection may adopt orders regulating the installation and use of outdoor lighting within five miles of the installation, base, or camp in any unincorporated territory of the county.
(c) The orders must be designed to protect against the use of outdoor lighting in a way that interferes with scientific astronomical research of the observatory or military and training activities of the military installation, base, or camp. In the orders, the commissioners court may:
(1) require that a permit be obtained from the county before the installation and use of certain types of outdoor lighting in a regulated area;
(2) establish a fee in an amount to cover the costs of administrating the order for the issuance of the permit;
(3) prohibit the use of a type of outdoor lighting that is incompatible with the effective use of the observatory or military installation, base, or camp;
(4) establish requirements for the shielding of outdoor lighting; and
(5) regulate the times during which certain types of outdoor lighting may be used.
(d) The commissioners court may apply more stringent standards for areas in which the use of outdoor lighting has a greater impact on observatory or military installation, base, or camp activities.
(e) The commissioners court may adopt an order under this subchapter only after conducting a public hearing on the proposed order. The court shall give at least two weeks’ public notice of the hearing.